What kind of worm is this?? (no bristle worm)

This is a discussion on What kind of worm is this?? (no bristle worm) within the Coral and Reef Creatures forums, part of the Advanced Saltwater Discussion category; -->
This guy would never completely come out of the rock but was white is color and smotth in apperance he was feeding on the ...

That is not a worm, that is a mollusk in the rock. It's a burrowing mollusk, imbeds itself in the rock. It's a detrivore. The portion you are seeing is the proboscus, and will come out at night to feed on debris on the rock. It's not harmful to your fish or your tank.

This one wasn't just me, my husband saw the picture and ID'd it on the spot. It's called having seen more than the average person, hundreds of hours of studying and research (this includes disection, autopsies, biopsies, etc) and a husband who has a degree in aquatic biology and handled part of my training himself.
The neat thing about saltwater is that it is forever changing, and it is so easy to find things in a tank that are undescribed by science as of yet. This just happened to be something we recognized and knew about. This has been my career for over 10 yrs now, and my husband's career for over 15 and we both learn something new every day. This is why we both encourage everyone to study the things they have on hand, watch your tank, learn about the things you see. Nobody can know it all, there is just simply too much of it out there, but anyone who takes the time can really learn a lot!